Nefarious individuals seek to compromise computing systems for a variety of reasons. One way such compromises can be achieved is through the distribution of malicious software to target computers which then execute the malicious software. One way to help protect a computing system from compromise is to prevent malicious software from reaching it. As one example, computer security companies offer products that use blacklists of known malicious software to intercept malicious software or otherwise prevent it from ultimately executing on a computing system. Unfortunately, such blacklists have limitations. As one example, attackers can make subtle changes to existing malicious software (e.g., that is present on a blacklist) resulting in a version of the malicious software that is not present on the blacklist.